One key difference that astronomers use to distinguish between brown dwarfs and high-mass planets is that:
A) brown dwarfs are all much larger in diameter than any planets
B) brown dwarfs shine quite brightly in visible light, while planets are only visible from the light they reflect
C) brown dwarfs are able to do deuterium fusion in their cores, while planets can't
D) brown dwarfs are much lower in mass than planets like Jupiter
E) brown dwarfs have a much lower luminosity than any planets
Section 17.4: Using Spectra to Measure Stellar Radius, Composition, and Motion

Question

Quizplus · Accepted Answer

Brown dwarfs are able to do deuterium fusion in their cores, while planets cannot. This means that if an object is found to be undergoing deuterium fusion, it is more likely to be classified as a brown dwarf rather than a planet. Other factors such as mass and luminosity may also be used to distinguish between the two, but deuterium fusion is a key difference that astronomers look for.

One Key Difference That Astronomers Use to Distinguish Between Brown